linux/include/asm-arm/arch-ixp4xx/timex.h
Deepak Saxena 9138dccbb9 [PATCH] Fix IXP4xx CLOCK_TICK_RATE
As pointed out in the following thread, the CLOCK_TICK_RATE setting for
IXP4xx is incorrect b/c the HW ignores the lowest 2 bits of the LATCH
value.

   http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2005-August/030950.html

Tnx to George Anziger and Egil Hjelmeland for finding the issue.

Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-23 20:06:33 -07:00

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399 B
C

/*
* linux/include/asm-arm/arch-ixp4xx/timex.h
*
*/
#include <asm/hardware.h>
/*
* We use IXP425 General purpose timer for our timer needs, it runs at
* 66.66... MHz. We do a convulted calculation of CLOCK_TICK_RATE b/c the
* timer register ignores the bottom 2 bits of the LATCH value.
*/
#define FREQ 66666666
#define CLOCK_TICK_RATE (((FREQ / HZ & ~IXP4XX_OST_RELOAD_MASK) + 1) * HZ)